The present invention relates to black-and-white silver salt photothermographic dry imaging materials having superior image quality and exhibiting superior uniformity without unevenness.
In the field of graphic arts and medical treatment, there have been concerns in processing of photographic film with respect to effluent produced from wet-processing of image-forming materials, and recently, reduction of the processing effluent is strongly demanded in terms of environmental protection and space saving.
There has been desired a photothermographic material for photographic use, capable of forming distinct black images exhibiting high sharpness, enabling efficient exposure by means of a laser imager or a laser image setter.
Known as such a technique is a silver salt photothermographic dry imaging material which comprises on a support an organic silver salt, light sensitive silver halide grains, and reducing agent, as described in U.S. Pat. Nos. 3,152,904 and 3,487,075, and D. Morgan, xe2x80x9cDry Silver Photographic Materialsxe2x80x9d (Handbook of Imaging Materials, Marcel Dekker, Inc. page 48, 1991) and JP-A No. 2001-272746 (hereinafter, the term, JP-A refers to Japanese Patent Application Publication). In such photothermographic materials, no solution type processing chemicals is used, providing a simple and environment friendly system to users.
These photothermographic materials, which comprise a photosensitive layer containing light-sensitive silver halide grains as a photosensor and an organic silver salt as a silver source, together with a reducing agent are thermally developed usually at a temperature of 80 to 140xc2x0 C. to form an image, without being further subjected to fixing.
However, when developed using commonly known apparatuses and methods, the foregoing photothermographic materials often result in non-uniform images. Specifically when continuously processed, such a tendency became marked, producing problems in uneven density. Such defects are permissible in the field applying texts and line images for the most part. However, in the field applying medical, industrial and graphic images, further enhanced levels of uniformity in density and color tone, stability of color tone (i.e., neutralness or natural blackness), and image quality have been desired. In this regard, techniques for enhancing uniformity in processed images, specifically, uniformity in neutral solid images are also disclosed in the foregoing literature.
Accordingly, it is an object of the present invention to provide a silver salt photothermographic dry imaging material (hereinafter, also denoted simply as photothermographic material) exhibiting enhanced image quality and superior uniformity without causing uneven density, an image recording method and image forming method by use thereof, and a preparation method thereof.
The object of the invention can be accomplished by the following constitution:
1. A silver salt photothermographic material comprising on a support a light-sensitive layer comprising a light-sensitive emulsion containing organic silver salt grains and light-sensitive silver halide grains, a reducing agent and a binder and a conductive layer, wherein the conductive layer contains at least one of compounds represented by the following formulas (2a) through (2e):
(Rf1)p"Parenopenst"Y"Parenclosest"(A1)qxe2x80x83xe2x80x83formula (2a)
wherein Rf1 represents a fluorine-containing substituent group; Y represents a linkage group containing no fluorine atom; A1 represents an anion group or its salt; p is an integer of 1 to 5 and q is an integer of 1 to 5, provided that A1 is not SO3K when p and q are each 1, Rf1 is xe2x80x94C8F17 and Y is xe2x80x94CH2CH2xe2x80x94;
(Rf2"Parenclosest"(A2)sxe2x80x83xe2x80x83formula (2b)
wherein Rf2 represents a fluorine-containing group; A2 represents an anion group or its salt; and s is an integer of 2 to 5;
LiO3S"Parenopenst"CF2"Parenclosest"mSO3Lixe2x80x83xe2x80x83formula (2c)
wherein m is an integer of 1 to 4;
MO3S"Parenopenst"CF2"Parenclosest"tSO3Mxe2x80x83xe2x80x83formula (2d)
wherein M represents H, Na, K or an ammonium group; t is a positive integer, provided that when M is H, t is 1 to 6 or 8, when M is Na, t is 4, when M is K, t is 1 to 6, and when M is an ammonium group, t is 1 to 8;
L[O3S"Parenopenst"CF2"Parenclosest"uSO3]xe2x80x83xe2x80x83formula (2e)
wherein L is Ba, Ca or Mg; u is a positive integer, provided that when L is Ba, u is 1 to 5, when L is Ca or Mg, u is 1 to 8;
2. The photothermographic material described above, wherein at least one of the light-sensitive layer and a layer adjacent thereto contains a compound represented by the following formula (1): 
wherein R1 represents an alkyl group; R2 represents a hydrogen atom, an alkyl group, or an acylamino group, provided that neither R1 nor R2 is 2-hydroxyphenylmethyl R3 represents a hydrogen atom, or an alkyl group; and R4 represents a substituent group.